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-rw-r--r--Eigen/src/Cholesky/LDLT.h59
-rw-r--r--Eigen/src/Cholesky/LLT.h58
-rw-r--r--Eigen/src/Core/ConditionEstimator.h215
-rw-r--r--Eigen/src/LU/FullPivLU.h13
-rw-r--r--Eigen/src/LU/PartialPivLU.h19
5 files changed, 337 insertions, 27 deletions
diff --git a/Eigen/src/Cholesky/LDLT.h b/Eigen/src/Cholesky/LDLT.h
index c3cc3746c..d246a459c 100644
--- a/Eigen/src/Cholesky/LDLT.h
+++ b/Eigen/src/Cholesky/LDLT.h
@@ -13,7 +13,7 @@
#ifndef EIGEN_LDLT_H
#define EIGEN_LDLT_H
-namespace Eigen {
+namespace Eigen {
namespace internal {
template<typename MatrixType, int UpLo> struct LDLT_Traits;
@@ -73,11 +73,11 @@ template<typename _MatrixType, int _UpLo> class LDLT
* The default constructor is useful in cases in which the user intends to
* perform decompositions via LDLT::compute(const MatrixType&).
*/
- LDLT()
- : m_matrix(),
- m_transpositions(),
+ LDLT()
+ : m_matrix(),
+ m_transpositions(),
m_sign(internal::ZeroSign),
- m_isInitialized(false)
+ m_isInitialized(false)
{}
/** \brief Default Constructor with memory preallocation
@@ -168,7 +168,7 @@ template<typename _MatrixType, int _UpLo> class LDLT
* \note_about_checking_solutions
*
* More precisely, this method solves \f$ A x = b \f$ using the decomposition \f$ A = P^T L D L^* P \f$
- * by solving the systems \f$ P^T y_1 = b \f$, \f$ L y_2 = y_1 \f$, \f$ D y_3 = y_2 \f$,
+ * by solving the systems \f$ P^T y_1 = b \f$, \f$ L y_2 = y_1 \f$, \f$ D y_3 = y_2 \f$,
* \f$ L^* y_4 = y_3 \f$ and \f$ P x = y_4 \f$ in succession. If the matrix \f$ A \f$ is singular, then
* \f$ D \f$ will also be singular (all the other matrices are invertible). In that case, the
* least-square solution of \f$ D y_3 = y_2 \f$ is computed. This does not mean that this function
@@ -192,6 +192,15 @@ template<typename _MatrixType, int _UpLo> class LDLT
template<typename InputType>
LDLT& compute(const EigenBase<InputType>& matrix);
+ /** \returns an estimate of the reciprocal condition number of the matrix of
+ * which *this is the LDLT decomposition.
+ */
+ RealScalar rcond() const
+ {
+ eigen_assert(m_isInitialized && "LDLT is not initialized.");
+ return ReciprocalConditionNumberEstimate(m_l1_norm, *this);
+ }
+
template <typename Derived>
LDLT& rankUpdate(const MatrixBase<Derived>& w, const RealScalar& alpha=1);
@@ -207,6 +216,11 @@ template<typename _MatrixType, int _UpLo> class LDLT
MatrixType reconstructedMatrix() const;
+ /** \returns the decomposition itself to allow generic code to do
+ * ldlt.adjoint().solve(rhs).
+ */
+ const LDLT<MatrixType, UpLo>& adjoint() const { return *this; };
+
inline Index rows() const { return m_matrix.rows(); }
inline Index cols() const { return m_matrix.cols(); }
@@ -220,7 +234,7 @@ template<typename _MatrixType, int _UpLo> class LDLT
eigen_assert(m_isInitialized && "LDLT is not initialized.");
return Success;
}
-
+
#ifndef EIGEN_PARSED_BY_DOXYGEN
template<typename RhsType, typename DstType>
EIGEN_DEVICE_FUNC
@@ -228,7 +242,7 @@ template<typename _MatrixType, int _UpLo> class LDLT
#endif
protected:
-
+
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
@@ -241,6 +255,7 @@ template<typename _MatrixType, int _UpLo> class LDLT
* is not stored), and the diagonal entries correspond to D.
*/
MatrixType m_matrix;
+ RealScalar m_l1_norm;
TranspositionType m_transpositions;
TmpMatrixType m_temporary;
internal::SignMatrix m_sign;
@@ -314,7 +329,7 @@ template<> struct ldlt_inplace<Lower>
if(rs>0)
A21.noalias() -= A20 * temp.head(k);
}
-
+
// In some previous versions of Eigen (e.g., 3.2.1), the scaling was omitted if the pivot
// was smaller than the cutoff value. However, since LDLT is not rank-revealing
// we should only make sure that we do not introduce INF or NaN values.
@@ -433,12 +448,32 @@ template<typename InputType>
LDLT<MatrixType,_UpLo>& LDLT<MatrixType,_UpLo>::compute(const EigenBase<InputType>& a)
{
check_template_parameters();
-
+
eigen_assert(a.rows()==a.cols());
const Index size = a.rows();
m_matrix = a.derived();
+ // Compute matrix L1 norm = max abs column sum.
+ m_l1_norm = RealScalar(0);
+ if (_UpLo == Lower) {
+ for (int col = 0; col < size; ++col) {
+ const RealScalar abs_col_sum = m_matrix.col(col).tail(size - col).template lpNorm<1>() +
+ m_matrix.row(col).head(col).template lpNorm<1>();
+ if (abs_col_sum > m_l1_norm) {
+ m_l1_norm = abs_col_sum;
+ }
+ }
+ } else {
+ for (int col = 0; col < a.cols(); ++col) {
+ const RealScalar abs_col_sum = m_matrix.col(col).head(col).template lpNorm<1>() +
+ m_matrix.row(col).tail(size - col).template lpNorm<1>();
+ if (abs_col_sum > m_l1_norm) {
+ m_l1_norm = abs_col_sum;
+ }
+ }
+ }
+
m_transpositions.resize(size);
m_isInitialized = false;
m_temporary.resize(size);
@@ -466,7 +501,7 @@ LDLT<MatrixType,_UpLo>& LDLT<MatrixType,_UpLo>::rankUpdate(const MatrixBase<Deri
eigen_assert(m_matrix.rows()==size);
}
else
- {
+ {
m_matrix.resize(size,size);
m_matrix.setZero();
m_transpositions.resize(size);
@@ -505,7 +540,7 @@ void LDLT<_MatrixType,_UpLo>::_solve_impl(const RhsType &rhs, DstType &dst) cons
// diagonal element is not well justified and leads to numerical issues in some cases.
// Moreover, Lapack's xSYTRS routines use 0 for the tolerance.
RealScalar tolerance = RealScalar(1) / NumTraits<RealScalar>::highest();
-
+
for (Index i = 0; i < vecD.size(); ++i)
{
if(abs(vecD(i)) > tolerance)
diff --git a/Eigen/src/Cholesky/LLT.h b/Eigen/src/Cholesky/LLT.h
index 74cf5bfe1..f88afe8b5 100644
--- a/Eigen/src/Cholesky/LLT.h
+++ b/Eigen/src/Cholesky/LLT.h
@@ -10,7 +10,7 @@
#ifndef EIGEN_LLT_H
#define EIGEN_LLT_H
-namespace Eigen {
+namespace Eigen {
namespace internal{
template<typename MatrixType, int UpLo> struct LLT_Traits;
@@ -40,7 +40,7 @@ template<typename MatrixType, int UpLo> struct LLT_Traits;
*
* Example: \include LLT_example.cpp
* Output: \verbinclude LLT_example.out
- *
+ *
* \sa MatrixBase::llt(), SelfAdjointView::llt(), class LDLT
*/
/* HEY THIS DOX IS DISABLED BECAUSE THERE's A BUG EITHER HERE OR IN LDLT ABOUT THAT (OR BOTH)
@@ -135,6 +135,16 @@ template<typename _MatrixType, int _UpLo> class LLT
template<typename InputType>
LLT& compute(const EigenBase<InputType>& matrix);
+ /** \returns an estimate of the reciprocal condition number of the matrix of
+ * which *this is the Cholesky decomposition.
+ */
+ RealScalar rcond() const
+ {
+ eigen_assert(m_isInitialized && "LLT is not initialized.");
+ eigen_assert(m_info == Success && "LLT failed because matrix appears to be negative");
+ return ReciprocalConditionNumberEstimate(m_l1_norm, *this);
+ }
+
/** \returns the LLT decomposition matrix
*
* TODO: document the storage layout
@@ -159,12 +169,17 @@ template<typename _MatrixType, int _UpLo> class LLT
return m_info;
}
+ /** \returns the decomposition itself to allow generic code to do
+ * llt.adjoint().solve(rhs).
+ */
+ const LLT<MatrixType, UpLo>& adjoint() const { return *this; };
+
inline Index rows() const { return m_matrix.rows(); }
inline Index cols() const { return m_matrix.cols(); }
template<typename VectorType>
LLT rankUpdate(const VectorType& vec, const RealScalar& sigma = 1);
-
+
#ifndef EIGEN_PARSED_BY_DOXYGEN
template<typename RhsType, typename DstType>
EIGEN_DEVICE_FUNC
@@ -172,17 +187,18 @@ template<typename _MatrixType, int _UpLo> class LLT
#endif
protected:
-
+
static void check_template_parameters()
{
EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar);
}
-
+
/** \internal
* Used to compute and store L
* The strict upper part is not used and even not initialized.
*/
MatrixType m_matrix;
+ RealScalar m_l1_norm;
bool m_isInitialized;
ComputationInfo m_info;
};
@@ -268,7 +284,7 @@ template<typename Scalar> struct llt_inplace<Scalar, Lower>
static Index unblocked(MatrixType& mat)
{
using std::sqrt;
-
+
eigen_assert(mat.rows()==mat.cols());
const Index size = mat.rows();
for(Index k = 0; k < size; ++k)
@@ -328,7 +344,7 @@ template<typename Scalar> struct llt_inplace<Scalar, Lower>
return Eigen::internal::llt_rank_update_lower(mat, vec, sigma);
}
};
-
+
template<typename Scalar> struct llt_inplace<Scalar, Upper>
{
typedef typename NumTraits<Scalar>::Real RealScalar;
@@ -387,12 +403,32 @@ template<typename InputType>
LLT<MatrixType,_UpLo>& LLT<MatrixType,_UpLo>::compute(const EigenBase<InputType>& a)
{
check_template_parameters();
-
+
eigen_assert(a.rows()==a.cols());
const Index size = a.rows();
m_matrix.resize(size, size);
m_matrix = a.derived();
+ // Compute matrix L1 norm = max abs column sum.
+ m_l1_norm = RealScalar(0);
+ if (_UpLo == Lower) {
+ for (int col = 0; col < size; ++col) {
+ const RealScalar abs_col_sum = m_matrix.col(col).tail(size - col).template lpNorm<1>() +
+ m_matrix.row(col).head(col).template lpNorm<1>();
+ if (abs_col_sum > m_l1_norm) {
+ m_l1_norm = abs_col_sum;
+ }
+ }
+ } else {
+ for (int col = 0; col < a.cols(); ++col) {
+ const RealScalar abs_col_sum = m_matrix.col(col).head(col).template lpNorm<1>() +
+ m_matrix.row(col).tail(size - col).template lpNorm<1>();
+ if (abs_col_sum > m_l1_norm) {
+ m_l1_norm = abs_col_sum;
+ }
+ }
+ }
+
m_isInitialized = true;
bool ok = Traits::inplace_decomposition(m_matrix);
m_info = ok ? Success : NumericalIssue;
@@ -419,7 +455,7 @@ LLT<_MatrixType,_UpLo> LLT<_MatrixType,_UpLo>::rankUpdate(const VectorType& v, c
return *this;
}
-
+
#ifndef EIGEN_PARSED_BY_DOXYGEN
template<typename _MatrixType,int _UpLo>
template<typename RhsType, typename DstType>
@@ -431,7 +467,7 @@ void LLT<_MatrixType,_UpLo>::_solve_impl(const RhsType &rhs, DstType &dst) const
#endif
/** \internal use x = llt_object.solve(x);
- *
+ *
* This is the \em in-place version of solve().
*
* \param bAndX represents both the right-hand side matrix b and result x.
@@ -483,7 +519,7 @@ SelfAdjointView<MatrixType, UpLo>::llt() const
return LLT<PlainObject,UpLo>(m_matrix);
}
#endif // __CUDACC__
-
+
} // end namespace Eigen
#endif // EIGEN_LLT_H
diff --git a/Eigen/src/Core/ConditionEstimator.h b/Eigen/src/Core/ConditionEstimator.h
new file mode 100644
index 000000000..c4c073fa2
--- /dev/null
+++ b/Eigen/src/Core/ConditionEstimator.h
@@ -0,0 +1,215 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2016 Rasmus Munk Larsen (rmlarsen@google.com)
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef EIGEN_CONDITIONESTIMATOR_H
+#define EIGEN_CONDITIONESTIMATOR_H
+
+namespace Eigen {
+
+namespace internal {
+template <typename MatrixType>
+inline typename MatrixType::RealScalar MatrixL1Norm(const MatrixType& matrix) {
+ return matrix.cwiseAbs().colwise().sum().maxCoeff();
+}
+
+template <typename Vector>
+inline typename Vector::RealScalar VectorL1Norm(const Vector& v) {
+ return v.template lpNorm<1>();
+}
+
+template <typename Vector, typename RealVector, bool IsComplex>
+struct SignOrUnity {
+ static inline Vector run(const Vector& v) {
+ const RealVector v_abs = v.cwiseAbs();
+ return (v_abs.array() == static_cast<typename Vector::RealScalar>(0))
+ .select(Vector::Ones(v.size()), v.cwiseQuotient(v_abs));
+ }
+};
+
+// Partial specialization to avoid elementwise division for real vectors.
+template <typename Vector>
+struct SignOrUnity<Vector, Vector, false> {
+ static inline Vector run(const Vector& v) {
+ return (v.array() < static_cast<typename Vector::RealScalar>(0))
+ .select(-Vector::Ones(v.size()), Vector::Ones(v.size()));
+ }
+};
+
+} // namespace internal
+
+/** \class ConditionEstimator
+ * \ingroup Core_Module
+ *
+ * \brief Condition number estimator.
+ *
+ * Computing a decomposition of a dense matrix takes O(n^3) operations, while
+ * this method estimates the condition number quickly and reliably in O(n^2)
+ * operations.
+ *
+ * \returns an estimate of the reciprocal condition number
+ * (1 / (||matrix||_1 * ||inv(matrix)||_1)) of matrix, given the matrix and
+ * its decomposition. Supports the following decompositions: FullPivLU,
+ * PartialPivLU, LDLT, and LLT.
+ *
+ * \sa FullPivLU, PartialPivLU, LDLT, LLT.
+ */
+template <typename Decomposition>
+typename Decomposition::RealScalar ReciprocalConditionNumberEstimate(
+ const typename Decomposition::MatrixType& matrix,
+ const Decomposition& dec) {
+ eigen_assert(matrix.rows() == dec.rows());
+ eigen_assert(matrix.cols() == dec.cols());
+ eigen_assert(matrix.rows() == matrix.cols());
+ if (dec.rows() <= 1) {
+ return static_cast<typename Decomposition::RealScalar>(1);
+ }
+ return ReciprocalConditionNumberEstimate(MatrixL1Norm(matrix), dec);
+}
+
+/** \class ConditionEstimator
+ * \ingroup Core_Module
+ *
+ * \brief Condition number estimator.
+ *
+ * Computing a decomposition of a dense matrix takes O(n^3) operations, while
+ * this method estimates the condition number quickly and reliably in O(n^2)
+ * operations.
+ *
+ * \returns an estimate of the reciprocal condition number
+ * (1 / (||matrix||_1 * ||inv(matrix)||_1)) of matrix, given ||matrix||_1 and
+ * its decomposition. Supports the following decompositions: FullPivLU,
+ * PartialPivLU, LDLT, and LLT.
+ *
+ * \sa FullPivLU, PartialPivLU, LDLT, LLT.
+ */
+template <typename Decomposition>
+typename Decomposition::RealScalar ReciprocalConditionNumberEstimate(
+ typename Decomposition::RealScalar matrix_norm, const Decomposition& dec) {
+ typedef typename Decomposition::RealScalar RealScalar;
+ eigen_assert(dec.rows() == dec.cols());
+ if (dec.rows() <= 1) {
+ return static_cast<RealScalar>(1);
+ }
+ if (matrix_norm == static_cast<RealScalar>(0)) {
+ return static_cast<RealScalar>(0);
+ }
+ const typename Decomposition::RealScalar inverse_matrix_norm =
+ InverseMatrixL1NormEstimate(dec);
+ return (inverse_matrix_norm == static_cast<RealScalar>(0)
+ ? static_cast<RealScalar>(0)
+ : (static_cast<RealScalar>(1) / inverse_matrix_norm) /
+ matrix_norm);
+}
+
+/**
+ * \returns an estimate of ||inv(matrix)||_1 given a decomposition of
+ * matrix that implements .solve() and .adjoint().solve() methods.
+ *
+ * The method implements Algorithms 4.1 and 5.1 from
+ * http://www.maths.manchester.ac.uk/~higham/narep/narep135.pdf
+ * which also forms the basis for the condition number estimators in
+ * LAPACK. Since at most 10 calls to the solve method of dec are
+ * performed, the total cost is O(dims^2), as opposed to O(dims^3)
+ * needed to compute the inverse matrix explicitly.
+ *
+ * The most common usage is in estimating the condition number
+ * ||matrix||_1 * ||inv(matrix)||_1. The first term ||matrix||_1 can be
+ * computed directly in O(n^2) operations.
+ *
+ * Supports the following decompositions: FullPivLU, PartialPivLU, LDLT, and
+ * LLT.
+ *
+ * \sa FullPivLU, PartialPivLU, LDLT, LLT.
+ */
+template <typename Decomposition>
+typename Decomposition::RealScalar InverseMatrixL1NormEstimate(
+ const Decomposition& dec) {
+ typedef typename Decomposition::MatrixType MatrixType;
+ typedef typename Decomposition::Scalar Scalar;
+ typedef typename Decomposition::RealScalar RealScalar;
+ typedef typename internal::plain_col_type<MatrixType>::type Vector;
+ typedef typename internal::plain_col_type<MatrixType, RealScalar>::type
+ RealVector;
+ const bool is_complex = (NumTraits<Scalar>::IsComplex != 0);
+
+ eigen_assert(dec.rows() == dec.cols());
+ const Index n = dec.rows();
+ if (n == 0) {
+ return 0;
+ }
+ Vector v = dec.solve(Vector::Ones(n) / static_cast<Scalar>(n));
+
+ // lower_bound is a lower bound on
+ // ||inv(matrix)||_1 = sup_v ||inv(matrix) v||_1 / ||v||_1
+ // and is the objective maximized by the ("super-") gradient ascent
+ // algorithm below.
+ RealScalar lower_bound = internal::VectorL1Norm(v);
+ if (n == 1) {
+ return lower_bound;
+ }
+ // Gradient ascent algorithm follows: We know that the optimum is achieved at
+ // one of the simplices v = e_i, so in each iteration we follow a
+ // super-gradient to move towards the optimal one.
+ RealScalar old_lower_bound = lower_bound;
+ Vector sign_vector(n);
+ Vector old_sign_vector;
+ Index v_max_abs_index = -1;
+ Index old_v_max_abs_index = v_max_abs_index;
+ for (int k = 0; k < 4; ++k) {
+ sign_vector = internal::SignOrUnity<Vector, RealVector, is_complex>::run(v);
+ if (k > 0 && !is_complex && sign_vector == old_sign_vector) {
+ // Break if the solution stagnated.
+ break;
+ }
+ // v_max_abs_index = argmax |real( inv(matrix)^T * sign_vector )|
+ v = dec.adjoint().solve(sign_vector);
+ v.real().cwiseAbs().maxCoeff(&v_max_abs_index);
+ if (v_max_abs_index == old_v_max_abs_index) {
+ // Break if the solution stagnated.
+ break;
+ }
+ // Move to the new simplex e_j, where j = v_max_abs_index.
+ v = dec.solve(Vector::Unit(n, v_max_abs_index)); // v = inv(matrix) * e_j.
+ lower_bound = internal::VectorL1Norm(v);
+ if (lower_bound <= old_lower_bound) {
+ // Break if the gradient step did not increase the lower_bound.
+ break;
+ }
+ if (!is_complex) {
+ old_sign_vector = sign_vector;
+ }
+ old_v_max_abs_index = v_max_abs_index;
+ old_lower_bound = lower_bound;
+ }
+ // The following calculates an independent estimate of ||matrix||_1 by
+ // multiplying matrix by a vector with entries of slowly increasing
+ // magnitude and alternating sign:
+ // v_i = (-1)^{i} (1 + (i / (dim-1))), i = 0,...,dim-1.
+ // This improvement to Hager's algorithm above is due to Higham. It was
+ // added to make the algorithm more robust in certain corner cases where
+ // large elements in the matrix might otherwise escape detection due to
+ // exact cancellation (especially when op and op_adjoint correspond to a
+ // sequence of backsubstitutions and permutations), which could cause
+ // Hager's algorithm to vastly underestimate ||matrix||_1.
+ Scalar alternating_sign(static_cast<RealScalar>(1));
+ for (Index i = 0; i < n; ++i) {
+ v[i] = alternating_sign *
+ (static_cast<RealScalar>(1) +
+ (static_cast<RealScalar>(i) / (static_cast<RealScalar>(n - 1))));
+ alternating_sign = -alternating_sign;
+ }
+ v = dec.solve(v);
+ const RealScalar alternate_lower_bound =
+ (2 * internal::VectorL1Norm(v)) / (3 * static_cast<RealScalar>(n));
+ return numext::maxi(lower_bound, alternate_lower_bound);
+}
+
+} // namespace Eigen
+
+#endif
diff --git a/Eigen/src/LU/FullPivLU.h b/Eigen/src/LU/FullPivLU.h
index 1721213d6..978a54eff 100644
--- a/Eigen/src/LU/FullPivLU.h
+++ b/Eigen/src/LU/FullPivLU.h
@@ -231,6 +231,15 @@ template<typename _MatrixType> class FullPivLU
return Solve<FullPivLU, Rhs>(*this, b.derived());
}
+ /** \returns an estimate of the reciprocal condition number of the matrix of which *this is
+ the LU decomposition.
+ */
+ inline RealScalar rcond() const
+ {
+ eigen_assert(m_isInitialized && "PartialPivLU is not initialized.");
+ return ReciprocalConditionNumberEstimate(m_l1_norm, *this);
+ }
+
/** \returns the determinant of the matrix of which
* *this is the LU decomposition. It has only linear complexity
* (that is, O(n) where n is the dimension of the square matrix)
@@ -410,6 +419,7 @@ template<typename _MatrixType> class FullPivLU
IntColVectorType m_rowsTranspositions;
IntRowVectorType m_colsTranspositions;
Index m_det_pq, m_nonzero_pivots;
+ RealScalar m_l1_norm;
RealScalar m_maxpivot, m_prescribedThreshold;
bool m_isInitialized, m_usePrescribedThreshold;
};
@@ -455,11 +465,12 @@ FullPivLU<MatrixType>& FullPivLU<MatrixType>::compute(const EigenBase<InputType>
// the permutations are stored as int indices, so just to be sure:
eigen_assert(matrix.rows()<=NumTraits<int>::highest() && matrix.cols()<=NumTraits<int>::highest());
- m_isInitialized = true;
m_lu = matrix.derived();
+ m_l1_norm = m_lu.cwiseAbs().colwise().sum().maxCoeff();
computeInPlace();
+ m_isInitialized = true;
return *this;
}
diff --git a/Eigen/src/LU/PartialPivLU.h b/Eigen/src/LU/PartialPivLU.h
index ab7797d2a..b22dd75fe 100644
--- a/Eigen/src/LU/PartialPivLU.h
+++ b/Eigen/src/LU/PartialPivLU.h
@@ -76,7 +76,6 @@ template<typename _MatrixType> class PartialPivLU
typedef Transpositions<RowsAtCompileTime, MaxRowsAtCompileTime> TranspositionType;
typedef typename MatrixType::PlainObject PlainObject;
-
/**
* \brief Default Constructor.
*
@@ -152,6 +151,15 @@ template<typename _MatrixType> class PartialPivLU
return Solve<PartialPivLU, Rhs>(*this, b.derived());
}
+ /** \returns an estimate of the reciprocal condition number of the matrix of which *this is
+ the LU decomposition.
+ */
+ inline RealScalar rcond() const
+ {
+ eigen_assert(m_isInitialized && "PartialPivLU is not initialized.");
+ return ReciprocalConditionNumberEstimate(m_l1_norm, *this);
+ }
+
/** \returns the inverse of the matrix of which *this is the LU decomposition.
*
* \warning The matrix being decomposed here is assumed to be invertible. If you need to check for
@@ -178,7 +186,7 @@ template<typename _MatrixType> class PartialPivLU
*
* \sa MatrixBase::determinant()
*/
- typename internal::traits<MatrixType>::Scalar determinant() const;
+ Scalar determinant() const;
MatrixType reconstructedMatrix() const;
@@ -247,6 +255,7 @@ template<typename _MatrixType> class PartialPivLU
PermutationType m_p;
TranspositionType m_rowsTranspositions;
Index m_det_p;
+ RealScalar m_l1_norm;
bool m_isInitialized;
};
@@ -256,6 +265,7 @@ PartialPivLU<MatrixType>::PartialPivLU()
m_p(),
m_rowsTranspositions(),
m_det_p(0),
+ m_l1_norm(0),
m_isInitialized(false)
{
}
@@ -266,6 +276,7 @@ PartialPivLU<MatrixType>::PartialPivLU(Index size)
m_p(size),
m_rowsTranspositions(size),
m_det_p(0),
+ m_l1_norm(0),
m_isInitialized(false)
{
}
@@ -277,6 +288,7 @@ PartialPivLU<MatrixType>::PartialPivLU(const EigenBase<InputType>& matrix)
m_p(matrix.rows()),
m_rowsTranspositions(matrix.rows()),
m_det_p(0),
+ m_l1_norm(0),
m_isInitialized(false)
{
compute(matrix.derived());
@@ -467,6 +479,7 @@ PartialPivLU<MatrixType>& PartialPivLU<MatrixType>::compute(const EigenBase<Inpu
eigen_assert(matrix.rows()<NumTraits<int>::highest());
m_lu = matrix.derived();
+ m_l1_norm = m_lu.cwiseAbs().colwise().sum().maxCoeff();
eigen_assert(matrix.rows() == matrix.cols() && "PartialPivLU is only for square (and moreover invertible) matrices");
const Index size = matrix.rows();
@@ -484,7 +497,7 @@ PartialPivLU<MatrixType>& PartialPivLU<MatrixType>::compute(const EigenBase<Inpu
}
template<typename MatrixType>
-typename internal::traits<MatrixType>::Scalar PartialPivLU<MatrixType>::determinant() const
+typename PartialPivLU<MatrixType>::Scalar PartialPivLU<MatrixType>::determinant() const
{
eigen_assert(m_isInitialized && "PartialPivLU is not initialized.");
return Scalar(m_det_p) * m_lu.diagonal().prod();